GPs will be called in to provide “emergency cover” for the ambulance service if a national strike over pay goes ahead next week.

Family doctors and hospital staff have been asked to step in if paramedics and ambulance technicians go ahead with a 12 hour strike planned for Thursday, as unions warned they will not back down.

It follows an emergency Cobra meeting chaired by the Health Secretary, at which contingency plans to maintain patient safety were discussed.

There are particular concerns about the safety of patients in London and the North West, where the ambulance service is most heavily unionised.

Health officials have asked GPs and hospitals in some parts of the country to supply staff, who will be given three hours’ training, before being asked to provide emergency cover for ambulance workers. Family doctors will be asked to work in call centres, helping to prioritise 999 calls, and hospital staff will be deployed in ambulances.

It came as unions issued formal notice of strike action, following three days of talks with Jeremy Hunt.

The health secretary has warned that paramedics will put lives at risk if they strike at a time when the NHS is under “unprecedented pressure”.

The unions are demanding a one per cent pay rise, which would cost the NHS more than £450 million. GMB, the union for NHS and ambulance staff, said talks will continue but that it would only call off industrial action if they were offered a new deal.

Earlier this week Mr Hunt pleaded with unions to call off the plans, which he said would “affect patient safety to an unacceptable level”. NHS England has warned that the strikes could “pose a real risk that patients with life-threatening conditions are harmed”.

The industrial action planned by Unison, Unite and the GMB means ambulance crews will strike from noon until midnight on Thursday, Jan 29, while hospital workers will walk out from 9am to 9pm on the same day. Ambulance unions could decide to extend their strike for a second day.

A second, 24-hour strike is scheduled for Wednesday, Feb 25, with work-to-rule actions planned for the weeks in between.

Up to 500,000 union members working in the NHS in England could take part in the strikes next week. Health officials have repeatedly urged the unions to abandon the plan, pointing out that a low turnout in ballots means just 13 per cent of members voted in favour of strike action.

NHS England’ s London area team has asked GPs to work in its operational centre, offering medical advice to call handlers, and helping to decide which 999 calls should receive an urgent response.

Hospital staff will be deployed in ambulances, depending on their experience.

On Thursday, health officials confirmed that they have written to every GP practice, asking for help.

A memo sent by officials to NHS organisations across the capital warns: “Considering the scale of this industrial action, and its potential impact on the ability of London Ambulance Service to deliver ambulance services and maintain patient safety over an extended period of time, the NHS across London needs to collectively identify and mobilise support for them.”

The British Medical Association said GPs said they did not have the skills to do such work, and were badly needed in their own practices.

Dr Richard Vautrey, deputy chairman of the BMA’s GPs committee, said: “GPs are under huge pressure, and taking them out of surgeries is going to make things worse – we aren’t paramedics and we aren’t trained for these kinds of roles.”

Other GPs said they had sympathy with ambulance workers and did not want to become “strike breakers”.

On Thursday, NHS inspectors put three GP surgeries into special measures for the first time after patients’ safety was found to be being placed at risk. The Care Quality Commission took the unprecedented step after uncovering “significant areas of concern” at practices in Reading, Liverpool and Sale, Cheshire.The three practices were run by Dr Srinivas Dharmana in Liverpool, Dr Michael Florin in Sale, Trafford, and The Priory Avenue Surgery in Caversham, Reading.

Dr Dharmana’s surgery was found to be inadequate for being safe, effective, caring, responsive and well-led. The practice was run by locum GPs because the doctor had not been involved in delivering care. But last night Dr Dharmana, 43, criticised the decision to name his practice as inadequate, and said he was not fully back at work after being stabbed outside surgery by a gang of five He said: "I do not mind them saying the service was not up to scratch but to put it in the public domain only seems to scare the public not help them.”

* The medical directors of 10 of England’s largest NHS trusts have written to health regulators warning that plans to change the way hospitals are funding will damage patient care, Health Service Journal has disclosed.

Regulators and health officials are due to decide next week whether to go ahead with plans. Under the proposals, revealed by The Telegraph, hospitals which provide specialist care to increasing numbers of patients will be reimbursed just half the cost of every extra case. The formula is part of attempts to divert more funds into out-of hospital care, and long-term prevention of disease. Hospital consultants have warned that 50 per cent funding rate for extra cases will cause devastation, given that the numbers of patients will inevitably rise with Britain's ageing population.